Description

The Diagnostic Autoamtion Inc. Cryptosporidium ELISA kit an in vitro immunoassay for the qualitative determination of Cryptosporidium antigen in feces. It is a double antibody (sandwich) ELISA using an anti-Cryptosporidium antibody to capture the antigen from the stool supernatant. A second anti-Cryptosporidium antibody is then added which sandwiches the captured antigen. This reaction is visualized by the addition of an antisecond antibody conjugated to peroxidase and the chromogen tetramethylbenzidine (TMB). The resulting blue color development indicates the presence of Cryptosporidium antigens being bound by the anti-Cryptosporidium antibodies.

Cryptosporidium is a coccidian parasite that is recognized as an important enteric pathogen. The organism causes an acute, though self-limiting infection in immunocompetent individuals. Incubation periods of 1 to 12 days have been reported with most oocyst shedding ending by day 21. Symptoms range from mild to severe diarrhea with a variety of complications. The infection in immunocompromised patients is much more severe and may often be life threatening. Passage of fluid, up to 12 liters per day, has been reported. Multiple pathways of Cryptosporidium transmission have been implicated. These include animal to human, water contamination and person-to-person. The latter may include contact between members of the same household, day care centers, and homosexual men. Diagnosis of Cryptosporidium infections was done originally by direct detection techniques. Of these, microscopic examination of stools using stains or fluorescence labeled antibodies has been the most common. However, this method relies on an experienced technician and subsequent observation of intact organisms. Because of the historically low proficiency of correct microscopic examinations, alternative diagnostic methods have been investigated. One important alternative has been the development of an antigen capture enzyme linked immunosorbent assay (ELISA) for use with stools. These tests, which have shown comparable sensitivity to experienced microscopic examinations, are fairly simple to perform and do not require the observation of intact organisms.

During the first incubation, Cryptosporidium antigens present in the stool supernatant are captured by antibodies attached to the wells. The second incubation adds an additional anti- Cryptosporidium antibody that \\\"sandwiches\\\" the antigen. The next incubation adds an anti-second antibody conjugated to peroxidase. After washings to remove unbound enzyme, a chromogen is added which develops a blue color in the presence of the enzyme complex and peroxide. The stop solution ends the reaction and turns the blue color to yellow.